board = ['小仙女','傻瓜','张权']
user_list= []
while 1:

    username = input('请输入用户名:')
    if username == 'q' or username == 'Q':
        print('程序结束')
        break
# 遍历 board ,每次用board中的元素去替换username的值
    for i in board:
        username = username.replace(i,'*'* len(i))
    pwd = input('请输入密码:')
    user_list.append(username)
    print('用户名{}'.format(username))
    print('密码{}'.format(pwd))
